"Can I tell you something?" he said. "I keep hearing that I'm going to be [in it but] nobody's contacted me.

"They don't understand that if I play Batman's father, and one terrible evening, when Batman, Bruce Wayne himself - the young one - is desperate, and the thunder's crashing, the lightning, I come in through the library window, which kind of springs open in the storm and I say, 'Bruce, I'm your father. And at one time I was Batman. I want you to look in that volume over there'.

"You know what I'm saying? People would stand up and cheer. But that's just, you know, a cock-eyed idea of mine."